The official Pokémon movie website has updated. Translations follow:

Story:

This summer, the emotional tale "Everyone's Story" will have an explosive birth,
following in the footsteps of "I Choose You!"

Once a year, a "wind festival" is held in Fura City, the city where people live together with the wind. While the ancient belief that the legendary Pokémon Lugia will appear and bring about the blessed wind on the final day of the festival still exists, the people that gather in the city participate in the festival while wrapped in their own thoughts......

Lisa, the highschooler and Pokémon rookie.
Kagachi, the braggart that just can't stop telling tall tales.
Trito, the timid researcher that lacks confidence.
Hisui, the old eccentric that hates Pokémon.
Largo, the mysterious little girl that hangs around in the forest all by herself.

These are the people that Satoshi and Pikachu meet.
That meeting makes everyone's story start moving forward.

Character Profiles:

Characters profiles
	SATOSHI A boy aiming to become the world's greatest Pokémon Master.
	LISA A highschooler and Pokémon rookie.
	KAGACHI A braggart that just can't stop telling tall tales.
	TRITO A timid researcher that lacks confidence.
	HISUI An old eccentric that hates Pokémon.
	LARGO A mysterious little girl that hangs around in the forest all by herself.
	LUGIA The legendary Pokémon that brings the blessed wind to the city.

Teaser and trailer

Teaser 2:

Trailer 1:

Source: http://www.pokemon-movie.jp/story/, http://www.pokemon-movie.jp/chara/ and http://www.pokemon-movie.jp/trailer